The present invention relates generally to railroad switch stands, and more particularly to a novel railroad switch stand having in one embodiment the capability for chest height handwheel or powered actuation, and in other embodiments having a low profile with provision for electrical, fluid pressure powered or manual actuation.
Since the advent of railroads, switch stands have been employed to selectively divert rail cars from a primary track route to a secondary track, such as a siding or the like, and vice versa. U.S. Pat. No. 401,671 illustrates one type of railway switch stand still in common usage. This type of switch stand is operated by lifting and rotating a weighted rod from one position to another, thereby having the significant disadvantage of subjecting the switchman to potential back and leg injury.
Another type of switch stand in common usage is known as the HIGHSTAR manufactured by Pettibone-Mulliken. This switch stand includes a vertical throw shaft with a link affixed to the lower end extending outwardly on opposed sides thereof. Each end of the link includes an upwardly extending boss selectively and pivotally received in a pivot hole defined in the outboard end of the switch throw rod. A pair of retaining brackets retain the throw rod engaged with the selected boss. The throw shaft also includes a vertically pivotal, lockable, outwardly extendable handle used as a lever to rotate the throw shaft. The upper end of the throw shaft supports a banner or target for indicating the position of the rail switch.
U.S. Pat. No. 1,325,396 discloses a switch stand which employs a rotatable wheel mounted at track level. This requires a switchman to bend over to operate the wheel, thereby subjecting the switchman to potential back injury. Additionally, this type of switch does not provide a mechanism for automatically locking the switch stand in the open or thrown position, or include means to indicate the exact position of the switch, such as in a position between its open and thrown positions.
Attempts to improve on prior commonly used switch stand designs have resulted in switch stands which have not met widespread acceptance and usage because of mechanical complexity and associated installation and maintenance costs. For example, U.S. Pat. No. 3,652,849 discloses a switch stand having a foot-operated, switch-connected lever movable to operate a rail switch between open and thrown positions. This type of switch stand, however, presents greater mechanical complexity than desired and may become inoperable if snow or gravel becomes piled under the foot pedals of the device.
U.S. Pat. No. 4,824,054, which is incorporated herein by reference, discloses a railroad switch stand of relatively simple yet highly effective construction and which has numerous advantages over prior switch stands. This switch stand is more easily operated by a switchman without bending over, and facilitates automatic locking and disconnection in the event a train runs through the switch when lined against it. This switch stand has a hand-operable rotatable throw wheel mounted at about normal chest height, means coupling the throw wheel with the throw rod for translating rotation of the throw wheel into longitudinal movement of the rod, a locking bar for selectively engaging and preventing rotation of the throw wheel, and shear means enabling disconnection of the throw rod if excessive axial force is applied thereto, such as by a rail car running through the switch when lined against it.